IDENTIFICATION OF A LECTIN THAT INDUCES CELL-DEATH IN DEVELOPING CHICKEN B-CELLS

The bursa of Fabricius is required for the development of a diverse B cell. repertoire in chickens. Bursal B cells are dependent on survival signals within the bursa and their removal from the bursa results in death by apoptosis. To find molecules that regulate B cell survival, a panel of mAb and lectins was screened for the ability to either accel erate or prevent B cell death in culture. The fucose-specific lectin A leuria aurantia agglutinin (AAA) rapidly rendered B cells permeable to propidium iodide. Incubation with the lectin also accelerated the app earance of internucleosomal DNA fragmentation and nuclear condensation , characteristics of apoptotic cell death. On Western blots the lectin detects a single protein band of similar to 48-50 kDa molecular weigh t. AAA detects fucose in an alpha 1-6 linkage and the restriction of t his fucose linkage to a single protein suggests that it may be functio nally important in the regulation of cell survival. (C) 1998 Academic Press.